5PSQ-062 Safety evaluation of pembrolizumab in monotherapy

Background and Importance Checkpoint inhibition immunotherapy (ICIs) have substantially improved the prognosis for patients with many advanced malignancies. Despite important clinical benefits, ICIs are associated with a unique spectrum of side effects known as immune-related adverse events (irAEs). IrAEs include dermatologic, gastrointestinal, hepatic, endocrine, and other less common inflammatory events. Therefore, prompt recognition and management of irAEs is important. Aim and Objectives To describe the occurrence of adverse events (AEs) during treatment with pembrolizumab monotherapy, regardless of indication, in routine clinical practice. Material and Methods We conducted a retrospective, observational study that included all patients treated with pembrolizumab from September 2022 to September 2023 at our centre. The variables collected were age, sex, previous immunological disease, number of cycles received, AE and degree of toxicity, as well as delays due to toxicity. The computerised clinical history was used for this purpose. Adverse events were classified according to the National Cancer Institute (NCI) Common Terminology Criteria for Adverse Events (CTCAE) classification. Results Data were collected from 44 patients (54.54% male) with a mean age of 71 years ± 10.9 SD. 29.54% diagnosed with lung adenocarcinoma, 27.27% with melanoma, 11.36% with renal cell carcinoma, 13.63% with non-small-cell epidermoid lung cancer, epidermoid carcinoma, 2.27% with Hodgkin's Lymphoma, 2.27% with gastric cancer and 2.27% with malignant mesothelioma. Mean treatment duration 42.65 weeks ± 13.1SD. 22 patients (50%) presented some AE, being grade 1: 59.45%, grade 2: 18.91% and grade 3–4: 21.6%. Grade 3–4 AEs were: three cases of skin toxicity (37.5%), two cases of neurotoxicity (25%), one case of arthralgias (12.5%), one case of limiting diarrhoea (12.5%) and one case of hepatitis (12.5%). Toxicity led to temporary discontinuation of treatment in six patients and definitive discontinuation in three patients. Conclusion and Relevance Treatment with pembrolizumab monotherapy proved safe. It was generally well tolerated and AEs were as expected according to technical sheet, with no new toxicity profiles noted. Cutaneous immune-related adverse events (irAEs) was the most common grade ≥3 adverse events. Only 8/44 patients had grade 3–4 AE, being limiting in 3/44 patients. References and/or Acknowledgements Conflict of Interest No conflict of interest.